Diagnosis

Introduction
Class I malocclusion
Class II malocclusion (overjet)
Class III malocclusion (underbite)
Crowding (crooked teeth)
Spacing (gaps)
Overbite(deepbite)
Overjet
Crossbite
Openbite
Impacted teeth
Missing teeth

Introduction
Orthodontic problems, which can result from genetic and environmental factors, must be diagnosed before treatment begins. Proper diagnosis starts by taking records, such as study model impressions, x-rays, and photographs. These records are then analyzed and presented to you to help you decide upon the most appropriate treatment.

Classifications
When classifying the front to back relationship of the upper teeth to the lower teeth, we use three classifications: I, II, and III.

Class I
Class I is the correct front to back relationship between the upper and lower teeth.

Class II(overjet)
Class II is an incorrect bite. This is where the upper teeth are further forward than the lower teeth. Some of the time, there is a convex appearance of the profile with a receding chin and lower lip. Class II problems can be due to insufficient growth of the lower jaw, an over growth of the upper jaw, or a combination of the two. In many cases, Class II problems are genetically inherited, and can be aggravated by environmental factors such as finger sucking. Class II problems are treated via growth redirection to bring the upper and lower teeth and jaws into harmony.

Class III (underbite)
Class III is also an incorrect bite. This is where the upper teeth are behind the lower teeth. There can be a concave appearance of the profile with a prominent chin. Class III problems are usually due to an overgrowth in the lower jaw, an undergrowth of the upper jaw, or a combination of the two. Like Class II problems, they can be genetically inherited.

Crowding (crooked teeth)
Crowding is due to the lack of space for all of the teeth to fit normally within the jaws. The teeth may be rotated or displaced. Crowding occurs when the teeth are larger than the available space. Crowding can be caused by early or late loss of primary teeth, or improper eruption of teeth.

Spacing (gaps)
Spacing, the opposite of crowding, is where you have gaps between your teeth. This generally occurs when the teeth are smaller than the available space. Spacing can also be caused by protrusive teeth, missing or impacted teeth, or abnormal tissue attachments to the gums. A space between the two front teeth is properly called a diastema.

Overbite (deepbite)
Overbite is the measurement of the overlap of the front teeth in a vertical dimension. A perfect overbite is where the upper front overlap 10 – 20% of the lower front teeth. It is not correct for the teeth to have zero overbite. But, it is far worst to have an overbite so deep, that the lower front teeth touch the gums behind the upper teeth.

Overjet
Overjet is also known as protrusion. This is where the upper front teeth are too far in front of the lower front teeth. This can be due to flared upper incisors, missing lower teeth, or a Class II malocclusion. Oral habits such as thumb or finger sucking or tongue thrusting can make this worst.

Crossbite
Crossbite is where the upper teeth bite on the inside of the lower teeth. This can occur with a single tooth or multiple teeth. Normally, the upper teeth fit to the outside of the lower teeth. A crossbite can occur with a single tooth or multiple teeth. It can occur in the front or on the sides. A crossbite on the side of the mouth can cause the lower jaw to be shifted to one side of the face. If not corrected, this can result in the jaw growing permanently into this shift and leave the person with a facial asymmetry that will last a lifetime. 

Openbite
Openbite is a measurement of the lack of vertical overlap of the front teeth. It is the opposite of overbite. With an openbite, the front teeth will not be touching, even though the back teeth are together as you bite.

Impacted Teeth
An impacted tooth is one that will not erupt into the mouth. They can be caused by improper positioning of the tooth bud, crowded teeth, or early loss of baby teeth. Wisdom teeth are the most commonly impacted teeth, with cuspids being the second most common.

Missing Teeth
This is the absence of a tooth or teeth that would normally be present. This can be caused by decay, trauma, or even a lack of the tooth to form in the jaw.